Waves

Waves

1. Transverse

   • Most waves are transverse e.g Light and EM waves
   • The vibrations are at 90 degrees to the direction energy is transferred
   • Vibrations move from side to side

2. Longitudinal

   • E.g sound and ultrasound waves
   • Vibrations are along the same direction
   • The waves contract

3. All waves carry and transfer energy in the direction they're travelling

   • They can also be used as signals to transfer information

4. Electromagnetic waves

   • All electromagnetic waves are transverse and move freely in a vacuum
   • The different colours of visible light depend on wavelength
     • red = longest wavelength violet = shortest wavelength

5. Uses

   • Radiowaves : -Broadcasting communications -Satellite transmissions
   • Microwaves : -Cooking -Communications -Satellite transmissions
   • Infrared : -Cooking -Optical fibres -Television remotes
   • Visible light : -Vision photography -Illumination
   • Ultraviolet : -Fluorescent lamps -Detecting forged bank notes -Disinfecting water
   • X-rays : -Airport security scanners -Medical X-rays
   • Gamma rays : -Sterilising food/medical equipment -Detection of cancer and its treatment

6. Dangers

   • Microwaves : Cause internal heating of body tissues
   • Infrared radiation : felt as heat and causes skin burns
   • X-rays : Damage cells, causes mutations (which may lead to cancer) and cell death

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